Close mainwindow from QDialog

Question

I have 2 different windows, my main window created in my first file and a QDialog window where the code is located in a second file... What I want to do is to be able from file2 to close the main window created in file1, close also the QDialog from file2 and create a new window in file3. The application must NOT quit.

Creating a new window with the code in file3 would be easy, I am not worried about that... The problem is that in file2, I'm unable to tell the main window to close.

Here is the code from the 2 files to be more clear...

main.py:

from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from PyQt5.QtGui import QRegion, QPalette, QPixmap, QBrush
import creation_partie
# import sys


class Menu(QMainWindow):
    def __init__(self):
        super(Menu, self).__init__()

     # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*

        self.init_ui()
        self.setWindowTitle("Bienvenue dans Skip-Bo!")

     # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*


    def center(self):
        # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*

    def quitter(self):
        self.close()

    def creer_nouvelle_partie(self):
        self.fenetre_creer_une_partie = creation_partie.NouvellePartie()
        self.fenetre_creer_une_partie.setModal(True)
        self.fenetre_creer_une_partie.show()

    def next_step(self):
        pass

    def init_ui(self):
        # --------------- Paramètres de la fenêtre --------------------
        self.resize(1280, 720)
        self.center()
        self.background_picture2.load('background_menu2.png')
        self.palette.setBrush(self.backgroundRole(), QBrush(self.background_picture2))
        self.setPalette(self.palette)
        # self.background_picture.setStyleSheet("background-image: url(background_menu.png);")
        # self.setCentralWidget(self.background_picture)
        # self.background_picture.setScene(self.scene)
        # # --------------- Fin des paramètres -------------------------

        # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*


if __name__ == '__main__':
    app = QApplication([])
    menu = Menu()
    menu.show()
    app.exec_()

creation_partie.py:

from PyQt5.QtWidgets import *
# from PyQt5.QtCore import *
# from PyQt5.QtGui import QRegion, QPalette, QPixmap, QBrush
import main

class NouvellePartie(QDialog):
    def __init__(self):
        super(NouvellePartie, self).__init__()
        # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*
        self.init_ui()

    def init_ui(self):
        # --------------- Paramètres de la fenêtre --------------------
        self.resize(640, 325)
        self.center()
        # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*

    def texte_change(self):
        # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*

    def center(self):
        # *SOME OTHER CODE NOT NEEDED FOR THIS QUESTION*

    def annuler(self):
        self.close()

    def confirmer(self):
        print("Yup")
        # send informations to the server backend of the game
        self.close()
        main.menu.close()




if __name__ == '__main__':
    app = QApplication([])
    nouvelle_partie = NouvellePartie()
    nouvelle_partie.show()
    app.exec_()

So... what I want to do, is that in the fonction confirmer in creation_partie.py be able to close menu from main.py. menu is a QMainWindow and fenetre_creer_une_partie is my QDialog.

Right now, the code compile and run fine until I click on the button that should close menu. PyCharm is not raising compiling error formain.menu.close()`, but when the code is about to be executed (at the moment I click my button), I get the following error:

module 'main' has no attribute 'menu'

How can I fix that?

P.S.: Sorry for the french variable and class names, I a french Canadian :) .

Thanks!

EDIT: Since the question has been closed, I will put my solution here: Basically, I created a function in ˙main.py˙ out of the class which close the main window. After that, the only thing I needed was to call that function in ˙creer_partie.py˙ by using ˙main.my-closing-function˙.